ZOOLOGY AND BOTANY, MK.'IioSCOI'Y. ETC. 



531 



Rejtds Metal-Microscope.* — This instrument is made by Messrs. 

 Reichert from Professor Rejto's designs. It is represented in fig. •")(> 

 as a Laboratory Microscope. Fig. 51 shows it, however, in a simplified 

 form, the middle parts, including the stage, having been removed to 

 facilitate application of the instrument to the direct examination of 

 large-sized objects. For the weaker magnifications, daylight or lamp- 

 light incident on the metal surface will suffice. But for stronger 

 powers illumination of the object must be performed with the special 

 apparatus inserted in the drawn-out tube. This apparatus can be in- 

 serted, or removed, as an ordinary ocular. It consists of a cylindrical 



Fig. 52. 



sleeve carrying a plane-parallel glass plate, inclined at 45° to the tube 

 axis, and an illuminating lens. The focal distance of this lens equals 

 the sum of the distances from the lens to the glass plate, and from the 

 glass plate to the objective. The light is set, preferably, at a distance 

 of 1 m. from the apparatus. An incandescent gas-mantle or a triple 

 burner will be found the most suitable, and must be placed on a special 

 stand adjustable as to height. It is desirable to enclose the light- 

 source in an iron or asbestos cylinder, with a lateral aperture of suit- 

 able size. This aperture must' be fitted with an illuminating lens of 

 parallelized light as required. In making the adjustments the light- 

 source must be first brought to the level of the illuminating apparatus B. 

 * Special Catalogue, Em 3, " Metall-Mikroskope," C. Reichert, Vienna, pp. 1-7. 



